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9. Prepare a brief speech on global warming. You have to deliver the speech in your class., Soln:, , The increase in the average temperature of the Earth’s surface is known as Global warming. It occurs due to the, increased concentration of greenhouse gases in the atmosphere. The greenhouse gases include methane, CO., and, water vapour. These gases trap the solar radiations released back by the earth, which results in keeping our planet, warm and helps in human survival. However, an increase in these gases can lead to an increase in the earth, temperature resulting in global warming., , 10. Describe the threat to the beauty of the Taj Mahal., , Soin:, , The major threat to the Taj Mahal is the acid rain. When the acid rain falls on the Taj, which is completely made, of marble, they react with marble to form a powder like substance which is then washed away by the rain. This, phenomenon is known as marble cancer. In addition, the soot particles emitted from the Mathura oil refinery, located near Agra is leading to the yellowing of Taj Mahal marble., , 11. Why does the increased level of nutrients in the water affect the survival of aquatic organisms?, , Soin:, , An increase in the level of nutrients in water body leads to an excessive increase in the population of algae in the, water body. When these algae die, they serve as food for decomposers. A lot of oxygen is utilized in this process,, , consequently leading to a decrease in the level of oxygen dissolved in the water body. This in-turn causes fishes, and aquatic organisms to die.